Module housing for improved electromagnetic radiation containment

Abstract

A module housing for minimizing electromagnetic radiation leakage and a transceiver module built with this housing are presented. The housing includes a cover and a base disengagably coupled to each other, and a first and second layer of sidewalls located between the cover and the base. The two layers of sidewalls have different dimensions from each other so that a printed circuit board is enclosed in a space formed by the base, the cover, and either only the second layer of sidewall or both the first and second layer of sidewalls, depending on the thickness of the board. Another aspect of the invention is a pcb coupled to a connector and a housing for the pcb that includes an electromagnetic radiation shield between electronic components on the pcb and the connector. The shield reduces the amount of radiation reaching the connector. Also disclosed is a method of building this module.

1. An optoelectronic transceiver comprising:
 a printed circuit board having a protruding subsection with electrical leads formed thereon; 
 optical components coupled to the printed circuit board, the optical components including at least one of a laser diode, a photodiode, and a lens; 
 a pin inserted into the printed circuit board from one side and soldered onto the printed circuit board, wherein the pin provides an electrical connection between the printed circuit board and a host device; 
 a housing including a base, a cover, and an inner layer and an outer layer of sidewalls located between the base and the cover, wherein the inner layer encloses a portion of the printed circuit board and the optical components that emit electromagnetic radiation and the outer layer covers a portion of the inner layer to further shield electromagnetic radiation, the inner layer and the outer layer allowing the electrical leads and the pin to extend through the housing; and 
 a connector secured to the housing, the connector having an opening to detachably receive the protruding subsection of the printed circuit board, wherein the connector supports a portion of the pin that provides the electrical connection between the printed circuit board and a host device. 
 
   
   
     2. A transceiver module, the module comprising:
 a printed circuit board with electrical components attached thereto, the printed circuit board having a transmission end and a host device end; 
 an optical subassembly in electrical communication with the printed circuit board; 
 a housing enclosing the printed circuit board, the housing including a base and a cover; 
 inner and outer sidewalls disposed between the base and the cover, and the inner and outer sidewalls configured to cooperate with the base and/or cover such that:
 a first radiation shield is defined about one of the electrical components when the printed circuit board has a first thickness; and 
 a pair of radiation shields are defined about one of the electrical components when the printed circuit board has a second thickness that is greater than the first thickness; and 
 
 an element that blocks at least a portion of a slot that is at least partially defined by the inner wall, the host device end of the printed circuit board being at least partially received in the slot. 
 
   
   
     3. An electronic module comprising:
 a printed circuit board having a transmission end and a device host end, the device host end detachably coupled to a connector through an opening formed in the connector, wherein the connector is made of a material that does not block electromagnetic radiation; and 
 a housing enclosing the printed circuit board, wherein the housing includes an electromagnetic radiation shield between electronic components on the printed circuit board and the connector to reduce electromagnetic radiation reaching the connector, the electromagnetic radiation shield having a pole that fits within a chassis ground hole formed in the printed circuit board to reduce an effective width of a gap in the electromagnetic radiation shield through which electromagnetic radiation reaches the connector. 
 
   
   
     4. The module of  claim 3  further comprising a slot in the electromagnetic radiation shield through which a portion of the device host end of the printed circuit board extends into the connector. 
   
   
     5. The module of  claim 4 , wherein the pole protrudes from the inner wall of the slot approximately halfway across the longest dimension of the gap, the pole entering a chassis-ground section of the printed circuit board to reduce an effective size of the gap through which electromagnetic radiation escapes. 
   
   
     6. The module of  claim 3 , wherein the housing includes a cover, a base, and two layers of sidewalls between the cover and the base, wherein a first of the two layers forms an electromagnetic radiation shield only if the printed circuit board is of a thickness above a threshold value. 
   
   
     7. The module of  claim 6 , wherein the first layer comprises an upper wall extending from the cover and an inner wall extending from the base, the upper wall and the inner wall coupled to each other by an isolated conductive region on the printed circuit board. 
   
   
     8. The module of  claim 3 , wherein the housing further comprises:
 a cover, a base disengagably coupled to the cover, and two layers of sidewalls located between the cover and the base to form a partially enclosed space between the cover and the base, wherein the two layers have different dimensions from each other. 
 
   
   
     9. The module housing of  claim 8 , wherein the two layers of sidewalls include an inner wall and an outer wall formed on an internal surface of the base. 
   
   
     10. The module housing of  claim 9 , further comprising an upper wall formed on the internal surface of the cover, wherein the upper wall forms a pattern that is substantially a mirror image of a pattern formed by the inner wall and is positioned to overlie the inner wall. 
   
   
     11. The module housing of  claim 10 , wherein the upper wall and the inner wall extend toward each other to form a first of the two layers. 
   
   
     12. The module housing of  claim 11 , wherein the outer wall forms the second of the two layers, the outer wall extending to the cover. 
   
   
     13. The module housing of  claim 11 , wherein the upper wall and the inner wall are separated by a gap that is approximately equal to the thickness of a printed circuit board. 
   
   
     14. The module housing of  claim 13 , further comprising a conductive rubber lining on at least one of the upper wall and the inner wall, wherein the lining covers the part of the walls closest to each other. 
   
   
     15. The module housing of  claim 13 , further comprising a conductive rubber lining located at an interface of the outer wall and the cover to seal any gaps at the interface.